36 BULLETIN OF THE 



out perceptible sculpture ; neither of the apertures appears to be oblique ; 

 both are circular. Lou. 4.0. Max. diaui. I.ii5. Oral diaui. 0.G2. Anal diani. 

 0.37 mm. 



Station 19, 310 fnis. 



It is really somewhat difficult to decide which is the anterior opening in this 

 species, unless the size be considered a criterion. 



C. sauridens Watson. 



St. Thomas, Challenger Exp., 390 fms. Blake Exp., Station 19, 310 t'ms. ; 

 off Cape San Antonio, 1,002 fms. Barbados, Ilassler Exjx, 100 lias. 



C- obesus Watson. 



St. Thomas, Challenger Exp., 390 fms. Blake Exp., Station 20, 220 fms. 



Siphonodentalium quadridentatum n. s. 



This species is best described by comparing it with S. tetraschistum "Watson, 

 to which it is nearly allied. The i:)resent form, which may prove eventually to 

 be a large race of Watson's species, seems to differ from it in its pro])ortionately 

 greater stourness and actually larger size, in the want of any sculpture on its 

 polished surface, and in the proportionally smaller and narrower slits at the 

 anfil end of the tube. The dimensions of quadridentatiim are : — Lon. 10.0. 

 Max. diaui. 1.3. Oral diam. 0.80. Anal diam. 0.4 mm. The same in Mr. 

 Watson's species are 7.7, 0.81, 0.75, and 0.4 mm. respectively. His specimen 

 came from "Fernando Noronha, 7-25 fms. ; ours is from Pourtales's dredgings 

 on the west coa.st of Florida, in 30 fms. 



In other respects than those mentioned, Watson's descrijjtiou and figure 

 agree almost exactly with our specimen. 



DENTALIUM. 



A. — Species with cylindrical tube. 



D. perlongum Dall. 



Bull. Mu.s. C'omp. Zoul., V. No. 6, p. 61 (name only). 1878. 



Shell solid, opaque white, shining, without sculpture except delicate irregu- 

 larities due to incremental lines ; oral aperture simjsle, nearly circular, its plane 

 quite or nearly at right angles to the axis ; anal ajjerture with a shallow notch 

 (in adult specimens) on the convex side ; tube very slightly curved. Lon. 

 50.0 to 80.0. Anal diam. 0.5 to 0.7. Oral diam. 3.5 mm. 



Station 41, 800 fuis. Station 46, 888 fins. Yucatan Strait, G40 fms. Sta- 

 tion 33, Lat. 24° 1', Lon. 88° 58' W., 1,568 fms. 



